Various artificial breeding techniques have been developed for mammals and specifically bovines, including artificial insemination (“AI”) and embryo transfer (“ET”).
Various breeds of cattle are often bred for specific purposes. For example, Angus, Brahman, Charolais, Hereford, Polled Hereford and Simmental are often bred for beef production. Holstein, Jersey, Guernsey, Ayrshire and Brown Swiss are often bred for the dairy industry. The following discussion is intended as background on cattle in general and this data may vary depending on the specific breed, food availability or the lack thereof and the weather.
In a natural setting, cows, heifers and at least one bull are free to roam in a pasture. The gestation for bovines is about 9½ months. After a calf is born, there is a delay of 2 or 3 months before the cow will come into heat (estrus). Heifers may have an even longer rebreeding delay. This delay in rebreeding allows the cow to produce milk for the new calf and bring hormones back to normal levels. After this delay (postpartum anestrous) the cow will usually come into heat every 18-24 days, unless interrupted by pregnancy or some problem.
Cows have two ovaries, but in the natural setting only one egg will be released from one ovary during each estrous cycle. The egg will travel down the respective oviduct. During heat, the cow is sexually attractive to both bulls and cows and will stand firm when other animals attempt to mount her. During heat, the three fibrous rings in the cow's cervix relax. Therefore when a bull mates with a cow in heat, his penis passes through the vulva, the posterior vagina, and the anterior vagina to a point very near the external cervical os. When the bull ejaculates, approximately 4-9 billion sperm are injected into the anterior vagina. Some of these sperm are transported through folds in the lining of the cervix then into the uterine horns (endometrium) of the uterus and finally into the oviducts. Conception occurs in the oviducts. The fertilized egg travels down the oviduct and embeds itself in the horn of the uterus where it develops until birth.
Conception rates for natural sexual breeding are very high because of the high number of sperm that are ejaculated per intercourse and because the bull will typically mate the cow or heifer on multiple occasions while she is in heat.
As previously mentioned, cattle are raised for a number of different purposes including dairy cattle, beef cattle, rodeo cattle, and seed cattle which are used to build a herd. The lifespan of cattle varies depending on the goals of the rancher. For example, beef cattle reach maturity in two to three years, but may be slaughtered after they reach a sufficient weight in 15-20 months. In the dairy industry, female calves from the best cows are saved for herd replacement, and bull calves are usually sold at a few days of age to be eventually slaughtered for beef. Mature dairy females are often slaughtered after 3 or 4 years of milk production. But beef seed stock cattle and rodeo cattle may have substantially longer lives to increase the number of high quality calves that are produced per cow. Left in a natural setting and well managed with adequate food and water, cattle will produce on average about one calf per year. Assuming the cow lives 10 years, and gives birth to her first calf in the second year of life, the average beef cow will produce about 7 to 8 calves over her lifespan. The average dairy cow will only produce about 2 to 3 calves in her lifetime due to the stresses of high lactation output.
To increase the value of a cow's calves beef cattle ranchers and dairymen utilize frozen semen from the most valuable bulls in the industry to breed their cows. Since frozen semen can be shipped commercially around the world, the best bulls can be mated to thousands of cows instead of the usual 20 to 40 under natural pasture mating conditions.
Cryopreservation techniques for semen are well known to those skilled in the art and will be briefly summarized. About 5 ml to about 15 ml of semen is collected from a bull using an artificial vagina. The semen is mixed with a suitable extender and cryoprotectant. Assuming about 10 ml of semen have been collected, it may be mixed with about 240 ml of TRILADYL® solution, which is an off the shelf product that is available from Minitube of America in Verona, Wis. (www.minitube.com) The Triladyl® solution contains an extender and a cryoprotectant, such as glycerol. The mixture of semen, extender and cryoprotectant is then placed in plastic straws and frozen. In the industry the contents of the frozen straw is generally referred to as frozen semen, although is also contains an extender and a cryoprotectant. The goal is to cryopreserve about 20 million motile sperm in a ½ ml semen straw.
Artificial insemination (AI) is the process whereby frozen semen is thawed, placed in a AI instrument, and manually passed through the vagina, then the cervix and ultimately into the body of the uterus where it is deposited. Only a few drops of semen is typically used per prior art AI session. Semen straws contain about ¼ or ½ ml of fluid and typically only one or two straws are used per prior art AI session. To increase the number of calves that a valuable cow can produce, embryo transfer (ET) techniques have been developed and are well know to those skilled in the art. Conventional embryo transfer techniques include injection of genetically valuable cows with suitable hormones which cause them to produce multiple eggs (oocytes) in a single estrous cycle. This process is often referred to as superovulation. Each cow is then artificially inseminated with semen from a valuable bull that has been cryopreserved using conventional cryopreservation techniques.
During superovulation, semen fertilizes some of the oocytes, which are then referred to as embryos. However, many of the eggs are not fertilized or they die shortly after fertilization. All of these unfertilized oocytes, dead embryos, and live embryos (collectively known as ova) are flushed from the cow with a liter or more of embryo flush solution (Embryo flush solution is sometimes also referred to as recovery solution, in the industry). Each live embryo that is recovered is either transferred fresh into a recipient cow or cryopreserved to be transferred later into a recipient cow. The recipient cow is a surrogate mother, used for development of the fertilized embryo, birth and rearing of the calf. The recipient cow is typically less expensive than the genetically valuable donor cow from which the embryos are harvested.
As previously mentioned, a cow in a natural setting with a life span of 10 years may produce about 7 calves over her lifetime. Using conventional procedures of embryo transfer, a donor cow with a life of 10 years may produce as many as 20 to 40 calves over her lifetime, with the help of multiple recipient cows.
AI produces conception rates of about 50 to 70% in single ovulating beef cattle, but only about 20-40% in dairy cattle. There is still room for improvement of artificial breeding techniques to improve rates of conception and therefore increase the total number of calves that a valuable donor cow can produce over her lifetime.
U.S. Pat. No. 5,147,229 to Mendoza is for a “Device to Facilitate Artificial Insemination of Bovines and Similar Animals”. As shown in Mendoza '229 at FIGS. 2 and 9, the AI instrument with an expanding balloon 2 is used to anchor the tip of the artificial insemination device in the cervix to create a seal. U.S. Pat. No. 6,071,231 to Mendoza is an improvement on Mendoza '229 and is for another insemination instrument with a balloon catheter as best seen in FIGS. 4-6. In Mendoza '231, at Column 2, beginning at line 5, the device is described as follows:                In operation, the frozen semen sample in a common plastic semen storage straw . . . is warmed and mixed with diluting fluid contained in an ampoule. The diluted semen is then loaded into the inseminating pipette by aspirating it out of the ampoule, whereupon it is pushed with air from a syringe out of the distal end of the pipette into the uterus of the animal through the anchored tip which is sealed against the cervix to prevent the fluid from leaking back.        
Mendoza '231 describes the process of the second patent as follows, beginning at Column 4, line 60: “With the aid of a plastic lighted speculum 32 to open the animal's vagina and view the interior, the device 29 is pressed part way into the cervix 33, the balloon 24 is inflated to form a seal with the cervix, and the dilution fluid is forced out of the syringe, pushing the semen sample and diluent into the uterus 34.” One advantage of the present artificial insemination instrument is that it does not require a lighted speculum in order to be inserted into the cow. Instead, the present AI instrument is inserted using the rectal palpation technique as described herein and as better seen in FIG. 5. It is therefore more economical to produce the present AI instrument because there is no need for the lighted speculum of Mendoza.
In Mendoza '299 and Mendoza '231, the AI instrument has a balloon type catheter used to position and seal the dispensing tip of the instrument in the cervix of the animal. The present invention does not use a catheter with a balloon, thus making is less costly to produce. Further, the dispensing tip of the present invention is either positioned at the body of the uterus or in the uterine horns, not the cervix.
In Mendoza '299, the amount of semen diluent is described as being contained in an ampoule, which is a small glass sealed vial. Mendoza '299 never discloses the amount of diluent that is in the ampoule. In Mendoza '231, the patent calls for an optimum total charge of semen and diluting fluid, but no specific amounts are ever disclosed, except that the diluting fluid is in an ampoule.
U.S. Pat. No. 7,056,279 is entitled “Device and Method for Artificial Insemination of Bovines and other Animals”. The '279 patent cites Mendoza '231 and describes insemination techniques as follows beginning at column 7, line 12:                In the classical insemination technique, the straw is thawed and opened at one side and inserted in the insemination instrument. The semen is expelled by moving the cotton plugs forward by means of a stainless steel rod. For the insemination instrument according to the invention, straws can be used. The straws are first thawed at 37° C., during one minute and then the semen (0.25 ml) is then expelled in an ampoule which contains 0.25 ml sodium citrate. The total of 0.5 ml is sufficient for a successful insemination by the deposition of 0.25 ml semen solution for each uterine horn.The '279 patent teaches that a total of about 1.0 ml of thawed cryopreserved semen and diluent are sufficient for AI of both uterine horns. Further, the '279 patent teaches that this mixture should be deposited near the uterotubal junction (See col. 8, lines 3-8).        
Applicant believes that there is still a need for improved AI procedures and apparatus. Specifically, the present invention uses substantially more insemination medium that the aforementioned prior art patents to flood the uterine horns. The present invention does not deposit the insemination medium near the uterotubal junction. Instead, the insemination medium of the present invention is deposited at the body of the uterus or at the posterior of each uterine horn.
U.S. Pat. No. 5,030,202 is for a “Lavage System” The term “lavage” means a therapeutic washing out of an organ or part. This patent applies to animals and in particular to equines (horses). Female horses (mares) sometimes have trouble conceiving immediately after giving birth (foaling). Apparently, part of the difficulty may be retained placenta or infection in the uterus. The uterine lavage apparatus 10 of FIG. 1 includes an inflatable cuff 42 (balloon) better seen in FIG. 2 which is the gravid uterus of a post partum mare. The inflatable cuff 42 is shown in the inflated position in FIG. 2. The cuff 42 is also shown in the inflated position in FIG. 2A which is the nongravid uterus of a mare. This washing technique (lavage) is particularly applicable to post partum mares and is not an artificial insemination procedure.
U.S. Pat. No. 2,566,632 is for an “Artificial Insemination Device”. At column 4 line 8, the patent states: “Thus, when the syringe 13 (Referring to FIG. 1) is operated and semen is drawn into the tubing 10, it will flow into the chamber 16 . . . ” “The size of the cavity or dome like chamber 16 may vary but it has been found desirable that this space or chamber have a capacity of about 1 cc. of semen, this being the proper amount for insertion in the animal.” Col. 4, lines 23-27. (1 cc equals 1 ml). The semen never enters the bore of the instrument beyond the chamber 16 or the syringe. (Col. 4, lines 55-58). Thus this prior art device uses only a 1 ml dose of semen, contrary to the teaching of the present patent application which recommends that the uterine horns be flooded with insemination medium to better increase the probability of conception. This prior art device does not place the insemination medium in the syringe.